Ronabea Aubl. includes three neotropical species of low shrubs found in wet forests and gallery forests from Belize to Amazonian Brazil. Ronabea has opposite leaves; raphides in its tissues; narrowly triangular, persistent, interpetiolar stipules; shortly cymose to subcapitate, few-flowered, axillary inflorescences with bracts; sessile, small, distylous flowers; white salverform corollas with five valvate lobes; bilocular ovaries with the basal ovules solitary in each locule; rather small, purple-black, drupaceous fruits; 2 unilocular pyrenes that are smooth on the adaxial surface and open by a preformed ventral lid; and oily endosperm (Taylor, 2004).

In spite of its small number of species, Ronabea has a rather complicated nomenclatural history as summarized by Taylor (2004). In particular R. latifolia is a rather frequently encountered species with a notable amount of morphological variation, especially in leaf size, shape, and pubescence, degree of expansion of the inflorescences, and corolla size, and it has received several different names. Here this species is circumscribed broadly, pending detailed future studies that will need to include field work.

Ronabea has long been considered closely related to or synonymous with Psychotria L., though a few authors have recognized it as a separate genus of Psychotrieae (e.g., Bremekamp 1934). Ronabea species were anomalous in Psychotria in their oily endosperm and also their combination of axillary inflorescences (i.e., borne in both axils at each node), persistent triangular stipules, and blue-black rather than red fruits. One study using molecular systematic data (Piesschaert et al., 2000) found Ronabea to be related to Lasianthus Jack. Ronabea has been most recently recognized as a separate genus of Lasiantheae (Taylor, 2004).